Android framework 中间件开发(三)

发布于：2025-05-18 ⋅ 阅读:(21) ⋅ 点赞:(0)

前两篇我们讲了中间件的开发和打包应用,

这边我们来讲一下在中间件中编写JNI

1.新建C++文件

找到frameworks\base\services\core\jni\路径,新建一个cpp文件,文件名为com_android_server_DarkControlService.cpp,里面就写两个测试函数,内容如下:

#define LOG_TAG "--==>>"
#include <utils/Log.h>
#include <log/log.h>
#include <jni.h>
#include <android_runtime/AndroidRuntime.h>
#include <nativehelper/JNIHelp.h>
#include "core_jni_helpers.h"

namespace android{

static jint android_server_DarkControlService_getSum(JNIEnv *env, jobject thiz, jint num1, jint num2)
{
    ALOGE("num1: %d, num2: %d",num1,num2);
	return num1+num2;
}

static void android_server_DarkControlService_testPrint(JNIEnv *env, jobject thiz,jstring str)
{
    const char* cstr = env->GetStringUTFChars(str, NULL);
    ALOGE("testPrint: %s",cstr);
    // 记得释放内存
    env->ReleaseStringUTFChars(str, cstr);
}

static const JNINativeMethod method_table[] = {
    { "native_getSum", "(II)I",
            (void *)android_server_DarkControlService_getSum },
    { "native_testPrint", "(Ljava/lang/String;)V",
            (void *) android_server_DarkControlService_testPrint },
};

int register_android_server_DarkControlService(JNIEnv *env)
{

    return jniRegisterNativeMethods(env, "com/android/server/DarkControlService",
            method_table, NELEM(method_table));
}

} // namespace android

里面有几个重要的地方,static const JNINativeMethod method_table[]和register_android_server_DarkControlService
method_table中需要将暴露给java的函数都在里面声明一下,注意每个函数的传参和返回值,

register_android_server_DarkControlService:这个是将这个C++代码和中间件的service类绑定起来